Pot burner and pilot assembly



Jan. l5, 1946. A. Pf LlvAR'-rAl. A 2,393,176

POT BURNER AND PILOT ASSEMBLY Filed Jan. 1a. i945 2 sheets-sheet 1 FIG. 6.

A V m @s "m Y o l m E (D mvEnrroRs ALLEN a Llwm AND CLEMENT R. GILMORE. A/JL/,MYM l ATTORNEYS Jan. 15, 1946. A. P. LlvAR ETAL POT BURNER AND PILOT ASSEMBLY 2 Sheets-Sheet 2 Filed Jan. 18, 1943 NN Y o w |\o o o o o hv o o 0\. do o o o o o o o o o o. o o o o o o o o o o o o o o l mvraNTRs ALLEN R. LNAR AND CLEMENT R. amMoRa; /WM/ naw.

ATTORNEYS Patented Jan. 1.5, 1946 2,393,176 Por BURNER AND rmo'r ASSEMBLY Allen r. Liver and clement n. Gilmore, Dayton,

Ohio, assignors to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application January 18, 1943, Serial No.' 472,674

12 claims. (o1. 15s- 91) This invention relates to improved liquid fuel burning apparatus.

In particular the invention pertains to apparams of this kind in which uquid fuel is vapor-I ized in a pot type container by reflected and retained heat from previously burned fuel and suit- A ably mixed with air to promote combustion of the resulting mixture at a predetermined location in the container.

One of the main objects of the invention is to provide a pilot in the burner pot of liquid fuel burning apparatus of this kind which is operated under natural, `or forced draft of a low order, in order to maintain an igniting flame and initial vaporizing heat between periods of normal combustion in thepot and under forced draft oi' a higher value during normal combustion periods so as to utilize the pilot as a vapor generator and to distribute the flame over a substantial area yhaving portions spaced relatively distant from the pilot.

Other objects of the invention are to utilize the forced air pilot draft to drive the vaporized fuel out of the pilot and toward the llame and fuel mixture outlet of the pot in` order to discourage the occurrence of combustion below a promote combustion' and to mix the fuel and initial air increment of the primary mixture.

Further objects of the invention are to provide in the lower portion of a rectangular pot'of this kind a plurality of air inlet holes for sup plying the remaining portion of the air content of the primary mixture and which are sadistributed as to maintain sufficient temperature at the bottom of the pot during commencement of combustion to prevent collecting and puddling of fuel; and to provide a distribution of the prif vmary air inlet holes which guards against buildpredetermined elevation in the pot; to provide a forced air pilot draft which increases the rate of the vaporization of fuel and correspondingly increases the capacity of the burner without requiring an increase in its dimensions, and to oliviate the necessity of accurately locating the floor of the pot so that fuel will be properly distributed thereover by forcing the fuel 'mainly in vaporized state from the pilot.

Additional objects of the invention are to provide a vaporizing burner of rectangular shape in order that a heat appliance of greater emoiency per pound of metal employed may be used; and to provide improved means for discharging a fuel'and air mixture into a rectangular pot of this type which is adapted to introduce the fuel mixture at one longitudinal extremity thereof and to forcefully drive it toward its opposite longitudinal extremity.

A further object of the invention is to provide suicient forced draft on the pilot of a fuel burning pot of this kind to keep the pilot free from excessive carbon deposits during and between periods of normal combustion. Another object is to provide a forced draft on the pilot of a iud fuel burning pot which serves to supply a portion of the air required to produce a primary fuel and air mixture of insufficient air content to ing up of the aircontent to an extent sulcient to support combustion in the lower portion of the pot at the end thereof remote from the pilot by the combined action of the forced pilot draft and the other primary air admission.

An additional object of the invention is to provide a combustion plate at the flame and fuel mixture outlet of the pot which is so curved in cross-section as to prevent air turbulence as the flame is emitted from the pot and to thus avoid flame pulling and sound disturbances.

An illustrative embodiment of the invention is shown in the accompanying drawings, ln which:

Eig. 1 is a perspective view, partly in section, of a hot air furnace having liquid fuel burning apparatus embodying the invention.

Fig. 2 is a vertical longitudinal sectional view of the fuel burning pot shown in Fig. i.

Fig. 3 is a transverse sectional view taken on the line 3 3 of Fig. 2.

Fig. d is a transverse sectional view taken on the line tif-Ei of Fig. 2.

Fig. 5 is a fragmentary vertical sectional view taken on the line 5 5 of Fig. 4.

Fig. 6 is a fragmentary horizontal sectional view taken on the line of Fig. 5.

The improved fluid fuel burning apparatus is illustrated in the drawings as embodied in a hot air furnace, generally designated by the numeral l0, of the type which has a blower il for forcing the air to be'heated through the furnace. The fluid fuel burning apparatus comprises a rectangular pot typel burner, generally designated by the numeral l2, which is disposed in a chamber I3 of the furnace l0 located above the blower Il. The flame, products of combustion and heat issue from the outlet of the pot type burner l2, enter a heat transfer compartment in the upper section of the furnace l0 and transfer heat to the air current propelled' through the furnace by the blower Il in a conventional manner.

The burner I2, as shown in Figures 2 to 6 in clusive, comprises a pot l@ of rectangular crosssection having an upper open extremity I5 surrounded by an outwardly extending flange I1. The horizontal cross-section of the rectangular pot is of substantially greater length than width and the length of the pot materially exceeds the depth thereof. Seated on the framelike flange I1, which surrounds the open upper extremity of the pot, is a sheet metal flame plate I8 having a central rectangular slot-dike opening I9 therein which extends from the rear or left end of the pot to a location substantially A of the length of the pot from the front or right end thereof. The rec tangular slot I9 forms a flame and fuel mixture outlet and is surrounded by a flange of arcuate cross-section. The contour of the cross-section of the ange 20 preferably conforms to streamlined curvature in order to fili in that space in which air turbulence would be created by emission of a flame and fuel mixture by the sharp edge of an outlet formed in a nat flame plate. By guarding against the creation of turbulence around the edge of the flame pattern, flame pulsation is greatly` reduced. 'Ihe bottom wall 2I of the pot I4 has a slight depression or well 22 located at its front end portion and substantially centrally of the floor of thepot. Disposed over the well 22 is a pilot.

housing generally designated by the numeral 23. The pilot housing, best shown in Fig. 5, comprises a sheet metal casing having a lower section 24 of 'substantially rectangular shape and an upper sectiori 25 of inverted yU-shaped cross-section, as shown in Fig. 4. Interposed between the upper and lower sections 25 and 24, respectively, is a partition 26 having a plurality of apertures 21 therethrough. The partition 26 also has a downwardly offset ridge '28.comprising a forwardly inclined side in which are formed a row of apertures 28 for directing air toward the front end of the` lower casing section 24. The pilot 23 is preferably detachably secured in the burner pot I4 by a bolt 30 extending through a sleeve 3| fixed to the top wall 32 and the partition 2l of the pilot housing.

The bolt 30 has a lowerv threaded end which isl threaded in a flange 33 of a bracket 34. The

bracket 34 is` riveted or otherwise suitably secured at 35 to the front end wall 35 of the pot I4.

A fitting 31` extending through an aperture formed in the front wall of the upper casing lsection 25 also extends through registering openings in the front wall 36 of the pot and in a mounting plate 38 by which the pot is supported and which is adapted tomount it in a furnace as illustrated in Fig. 1. The external end of the fitting 31 is threaded for connection with a pipe or other suitable conduit 39--by which a forced draft ofair is supplied to the upper casing section of the pilot housing from a source hereafter set forth. Formed on the front wall 36 of the pot I 4 at the lower extremity thereof is a tubular boss 40 having a central passage leading to the interior of the lower casing section of the pilot and provided with threads for receiving a nipple 4I by which a fluid fuel supply conduit 42 is detachably connected to the fuel burner.

The front wall of the lower casing section 24 of the pnothas an moet Opening as facing the longitudinal extremity of the pot I4 opposite that at which the pilot is located.

Provided in the opposite longitudinal side walls 44 of the pot I4 is a lowerrow of primary air inlet holes 45 which extend from a location substantially directly below the front longitudinal extremity of the rectangular slot or flame outlet opening I9 lto a location substantially adjacent the rear end wall 46 of the pot. Four additional rows of primary air inlet openings 41 are located above the lower row of'inlet holes 45. The uppermost row of primary air inlet holes 41 extends from a location below the front extremity of the slot I9 to a location spaced from the rear wall 46 of the pot and each successively adjacent lower row of holes 41 is spaced a greater distance from the rear end wall 46 of the pot than the upper adjacent row. With thisarrangement, the rows of primary air inlet holes 41 terminate on a line inclined rearwardlywith respect to the length of the pot I4 and-there is a decrease in the amount of primary air admitted at the rear end of the pot to compensate for the quantity of primary air which tends to be forced toward the rear .end of the pot by the forced draft of the pilot-as well as the accumulation of primary air admitted through the row of openings 45 and 41. The decrease in the number of holes at the rear end portion of the pot thus prevents unintended formation of a fue] and air mixture of combustible proportions at a low level in the rear end portion of the pot. The lowermost row of primary air inlet openings 45 serves to assure the admission of a sufllcient primary air supply throughout the length-of the spect tothe main body portions o f the side walls 44 in order to direct the fiowof air through the apertures 48 inwardly of the pot and upwardly toward the flame outlet thereof.

The body portion of the pot I 4 is enclosed in a casing, generally designated by the numeral 50, which comprises opposite longitudinal sides and rear end walls5I. 52, and 33 each provided with an inwardly extending flange 54 upon which the flanges I 1 of the pot rest. The flame plate I8, the flanges Il' of the pot and flanges 54 of the casing 50V are detachably secured together in airtight relationship by bolts 55 as illustrated in Figs. 2, 3 and 4. The mounting plate 38 forms the front end wall of the lcasing 5U, as illustrated in Fig., 5, and the lower wall 56 of the casing 50 has a flange 5l secured by bolts 58 to the mounting plate.

As illustrated in Figs. l and 5, the mounting plate. is provided with an aperture 59 leading to the interior of the casing 50 and through which extends a discharge tube 6U of a blower 6I. The blower 6I supplies a forced draft of air to the interior of. the casing 50 which is admitted to the interior of the pot I4 through the primary air inlet openings 45 and 41 and secondary air inlet openings 48. The pilot draft tube 3B is connected with the discharge side of the casing of the blower 6| so as to supply a forced air draft to the interior of the pilot housing 23.

In Fig. l of the drawings is illustrated dia- 'grammatically a control system for the uid fuel burning apparatus. This control system includes a solenoid valve 62 in a fuel line 63 which is connected with the fluid fuel supply tube 42. A by pass passage is provided around the valve 62 by a mined temperature may be completely `pilot increases the rate suitable temperature responsive mechanism in-4 cluding a thermostat 68 and relay 68 to simultaneously open the valve v62 and actuate the' blower 6I when the thermostat 6B calls for heat.

After the enclosure to which heated air is supi plied by the furnace I has reached a predeterthe valve 82 is closed in accordance with conventional fluid fuel burner control performance, and operation of the blower 6I discontinued or continued at a lower speed as desired. If operation of the blower is discontinued between normal combustion periods the fuel supplied to 'the'pilot housing 23 through the by-pass'M mixes with air supplied through the tube 39 to the pilot housing 23 by gravity, there being suicient fuel and air mixture to maintain the pilot lighted and heated sufficiently to initiate vaporization of fuel at the commencement of -a normal combustion period. If the blower 6| is reduced to part speed when the of forced draft of air to the pilot housing between normal combustion periods. During normal combustion periods the fluid fuel is vaporized and mixed with air entering the pilot housingl and 45 and t1 is insufficient to support combustion at a location in the pot below the upper extremity thereof. The secondary air inlet openings 68 supply an additional quantity of air to the pri mary fuel and air mixture raising its air content to combustible proportions and the mixture burns through the slot IQ and produces a flame extending the full length of the slot and projecting substantially above the latter. The pilot serves to produce a mixture of fuel vapor normal combustion' operations and to maintain an igniting light between combustionA operations as well as-to maintain the temperature of the pilot and portions of the pot in the vicinity of the latter at a sufliciently high value to encourage fuel vaporization during the initiall stages of a combustion period. The forced pilot draft drives the fuel and air mixture produced in and imrne`u miately in front ofthe pilot toward the rear end of the pot and also tends to force it upwardly toward the outlet or slot i9 of the pot thus deterring burning of fuel at a low elevation in the pot. A combined pilot and fuel and air mixing device of this kind having a forced pilot draft enables the use of a pot of rectangular cross-section having substantially greater length than transverse' dimensions and secures distribution of the fuel and air mixture throughout the length of the pot and over the entire length of an elongated flame outlet. The provision of a pilot maintains a clean flame during pilot operation and prevents the formation of carbon in and about the pilot housing and pot during normal combustion operation. The air pressure on the of vaporization of fuel and and air during forced draft` on theV valve t2 is closed, then there is present a supply 1 thus increases the, capacity of the burner without requiring an increase. in its size. Inasmuch as fuel vapor is forcefully discharged from the. pilot housing by the pilot draft the disposition of the floor of the pot with respect to a horizontal plane is not critical.

Although but one embodiment of the invention is herein shown and described, it will be understood that various changes in the sequence of operations, steps and materials employed may be made without departing from the spirit of the invention.

We claim:

l. A liquid fuel burner of the pot type comprising a rectangular fuel burning pot having av fuel mixture and flame outlet slot in its upper wall, a pilot housing in said pot adlacent one end wall comprising a casing having an outlet facing the opposite end wall of said -potv for directing fuel mixture `toward the latter and having a perforated partition dividing said casing into fuel and air receiving compartments, means for supplying liquid fuel to said fuel compartment, and means for discharging a forced air draft into said air compartment for producing a fuel and air mixture in said pilot housing and driving it through said pilot outlet toward said last mentioned end of said pot, some of the perforations of said partition being disposed to 'direct air jets away from said pilot outlet for producing turbulence in said pilot housing.

2. A liquid fuel burner of the pot type comprising a rectangular fuel burning pot having a fuel mixture and flame outlet slot in its upper wall, a pilot housing in said pot adjacent one end thereof having an outlet facing the opposite end of said pot for directing fuel and air-mixture toward the latter, means for supplying liquid fuel to said pilot housing. means for discharging a forced air draft into said pilot housing for producing an initial fuel and air mixture of relatively small air content and driving the same through said pilot outlet, the lateral side walls of said pot having a series of secondary air inlet openings adjacent said slot and successive rows of primary air openings below said secondary air openings, the lower row of primary air inlet openings extending substantially from 'said pilot housing to within close proximity to said opposite end of said pot, the next adjacent row terminating inl substantially greater spaced relation to said 0P- than the -row below it.

3. Liquid fuel burning apparatus comprising a casing havingv an opening in its upper side, aI

blower for discharging a forced air draft into said casing, a lfuel burning pot disposed in said opening having a flame outlet at its upper ex- 'tremity, said pot having opposite end Walls and` having spaced side walls provided with primary air inlet openings and secondary air inlet openings between the former and said flame outlet all communicating with the interior of said casing 'for receiving air from said blower, a pilot memb'er located adjacent one of said end walls of'said pot comprising a casing having impervious ex" ternal walls, one of said external walls of said pilotmember being provided with an outlet opene ing facing the other end wall of said pot, means for supplying liquid fuel to and means for conducting a forced -air draft to said pilot member for producing a fuel and air said pilot member,

mixture therein and driving said mixture from said piloty member toward said last mentioned 'end wall of said pot, the combined airv supply through said last mentioned means and said primary'air inlet openings being insuillcient to support combustion during normal combustion operation of said burner. l

4. Liquid fuel burning apparatus comprising a casing having an opening in its upper side, a. blower for discharging a forced air draft into said casing, a fuel burning pot disposed in said opening having a. flame outlet at its upper extremity, said pot having opposite end walls and having side walls provided with primary air inlet openings and secondary air inlet openings between the former and said ilame outlet all communicating with the interior of said casing for receiving air from said blower, a pilot member located adjacent one of said end wallsof saidpot, means for supplying liquid fuel to said pilot member, means for conducting a forced air draft from said blower to said pilot member for producing a fuel and air mixture therein and driving said mixturefrom said pilot member toward the other end wall of said pot, the combined air supply through said last mentioned means and said primary air inlet openings being insuillcient to support combustion within saidL pot during normal combustion'operation of said burner, and control mechanism for said liquid fuel supply means and blower adapted to reduce the supply of fuel and air to said pilot member for discontinuing normal combustion operation of said burner and tobring the fuel and air mixture in saidpilot member to a combustible state for maintaining the pilot lighted between periods of normal combustion operation.

5. Liquid fuel burning apparatus comprising a fuel burning pot having a ame outlet at its upper extremity and an adjacent combustion zone immediately below the latter, `said pot having opposite end walls and having side walls provided with primary air inlet openings and secondary air inlet openings between the latter and said ame outlet, means for discharging air under pressure through said primary and secondary air inlet openings, a pilot member in said pot located adjacent one of said end walls comprising a hollow casing having impervious exterior walls and a perforated partition dividing its interior into upper and lower air and fuel receiving chambers,

respectively, said lower fuel receiving chamber having an outlet facing the other end wall of said pot, means for supplying liquid fuel to said lower chamber of said pilot member, means -for discharging a forced air draft into said upper chamber of said pilot member and downwardly through the perforations of said partition for vaporizing fuel in said lower chamber and driving the resulting vaporlzed fuel through said pilot outlet toward said last mentioned end wall of saidpot, the combined air supply from said primary inlet openings and through said last mentioned means being insufficient to support combustion in said pot below said combustion zone.

6. Liquid fuel burning apparatus comprising a fuel burning pot having a. name outlet at its upper extremity and an adjacent combustion zone immediately below the latter, said pot having opposite end walls and having side walls provided with primary air inlet openings and secondary air inlet openings between the latter and said flame outlet, means for discharging air under pressure throughv said primary and secondary air inlet casing a perforated partition thereindlviding its interior into fuel and air receiving pilot outlet toward said last mentioned end wall of said pot, the combined air supply through said primary inlet openings and through said last mentioned means being insuihcient to support combustionin said -pot below said. combustion zone,and control mechanism for said liquid fuel supply and forced air draft discharge means adapted to reduce the supply of fuel and air to said pilot member for discontinuing combustion at said combustion zone and to bring the fuel and air mixture in said pilot member to a combustible state for maintaining the pilot lighted between periods of combustion at said combustion zone 7. vLiquid fuel burning apparatus comprising a casing having a rectangular opening in its upper side, a blower for discharging a forced air draft into said casing, a rectangular fuel burning pot extending into said opening having its main body portion disposed in said casing and having a llame outlet at its upper extremity extending from one end of said pot to a location spaced from its opposite end, the lateral side walls of said pot having a row of secondary air inlet openings therein communicatingV with the interior of said casing and extending from said first mentioned end of said pot throughout the length of said flame outlet and having a series of primary air inlet openings below said secondary air inlet openings, the number of primary air inlet openings in said series being reduced toward the first mentioned end of said pot, a hollow housing member disposed in said pot at a location between said opposite end of said pot and the adjacent end of said flame outlet and having a discharge opening facing said first mentioned end of said pot, means for supplying liquid fuel to said casing, and means for discharging a forced air draft into said casing for vaporizing fuel therein and driving a fuel and air mixture throughthe discharge opening' of said housing member toward said first mentioned end of said pot.

8. Liquid fuel burning apparatus comprising a casing having a rectangular opening in its upper from its opposite end, the lateral side walls of said pot having a row of secondary air inlet openings therein communicating with the interior of said casing and extending from said first mentioned end oi said pot throughout the length of openings, a pilot memberin said pot located adjacent one of said end walls comprising a hollow said flame outlet and having a series of primary air inlet openings below said secondary air inlet openings, the number of primary air inlet open- 4 ings in said series being reduced toward the first mentioned end of said pot, a hollow housing member disposed in said pot at a location between said opposite end of said pot and the adjacent end of said flame outlet and having a discharge opening facing said first mentioned end of said pot, means for supplying liquid fuel to said casing,

means for discharging a forced air draft into said casing for vaporizing fuel therein and driving a fuel and air mixture through the discharge opening of said housing member toward said first mentioned end of said pot, and aflange of curvilinear cross-section extending upwardly from and surrounding said llame outlet for guarding against noise creating turbulence in the air surrounding the flame emitted through said flame outlet. Y v

9. A liquid fuel burner of the pot type comprising a fuel burning pot having a fuel mixture and flame outlet in its upper side, a pilot housing in said pot including an apertured partition dividing the interior thereof into upper and lower air and fuel-receiving compartments, respectively, and having an outlet leading from said lower compartment and facing a wall portion of said pot spaced from pilot housing for directing fuel mixture toward said wall portion, means for supplying liquid fueltothe lower compartment of said pilot housing, and means for discharging a forced air draft into the upper compartment of said pilot housing and downwardly through said partition at a iocationabove said liquid 4fuel supply for producing a fuel and air mixture in said lower compartment and driving said mixture through said pilot outlet toward said wall portion of said pot.

10. A liquid fuel burner of the pot type comprising a fuel burning pot having spacedside and end walls a'nd including a concaved oor portion and having a chamber immediately above said oor portion for accommodating a fuel and air 'mixture of non-combustible proportions during normal combustion operation of said burner, said pot having a llame outlet in its upper side, means l in said pot providing anenclosure therein adjacent one end wall of said pct for receiving liquid fuel, said enclosure having an outlet facing the opposite end wall of said pot and having an open lower side disposed adjacent the floor of said pot and over the concaved portion thereof, means for dr'attinto said casing, a fuel burning pot disposed in said casing having a flame outlet at its upper extremity, said pot having opposite end wallsl and having spaced side walls provided with primary air inlet openings and secondary air inlet openings betweenthe former and said flame outlet all communicating with the interiorfof said cas- `ing for receiving air propelled by said blower, means in said pot providing a pilot chamber ad-. jacent one of said end walls, said chamber hav- I ing a wall provided with an outlet opening facing the other end wall of said pot, and means for supplying liquid fuel to said pilot chamber, said pilot chamber having an air inlet for admitting thereinto air propelled by said blower for producing a fuel and air mixture in said pilot chamber and for driving said mixture from the latter toward said last mentioned end wall of said pot, the combined air supplythrough said pilot chamber and said primary air inlet openings being insufficient to support combustion in said pot during normal combustion operation of said burner.

v 12. Liquid fuel burning apparatus comprising a casing, a blower for discharging a forced air draft into saidcasing, a fuel burning pot disposed-in 'said casing having a flame outlet 'at its upper extremity, said pot having opposite end walls and having spaced side walls provided with primary air inlet openings and secondary-air inlet openings between the former and said flame outlet'all communicating with the linterior of said casing for receiving air propelled bysaid blower, means in said pot providing a pilot chamber adjacent one of said end walls, said chamber having a wall provided with an outlet opening facing the other end wall of said pot, means for supplying liquid fuel'to said pilot chamber, said pilot chamber supplying liquid fuel into said enclosure and the concaved portion of said door, means for dis `charging a forced draft into said enclosure for producing an initial fuel and air mixture in said enclosure and for driving said mixture lthrough the outlet of said enclosure towardsaid opposite end of said pot, the side walls of said pot beinev provided with primary air inlet openings for supplementing the air content of the mixture in said non-combustible mixture chamber and with a plurality of secondary air inlet openings at a location between said chamber and the flame outlhaving an air inlet for admitting thereinto air propelled by said blower for. producing a fuel and air mixture in said pilot chamber and for driving said mixture from the latter toward said last mentioned end wall of said pot, the combined airsupply through said pilot chamber and said primary air inlet openings being insuflicient to support combustion at a location in said -pot substantially below said secondary air inlet openings dur- `ing combustion at said combustion zone, and control mechanism for said liquid fuel supply means and blower adapted to reduce the supply of fuel and air to said pilot chamber for discontinuing combustion at the vicinity of said secondary air inlet openings and to bring the fuel and air mixture in said pilot chamber to a combustible state for maintaining a pilot light between periods of' combustion at the vicinity of said secondary air inlet openings.

ALLEN P. LIVAR. `Cllils'ililENT R. GILMORE. 

